John A. Roebling by Dr
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GREAT ACHIEVEMENTS notable structural engineers John A. Roebling By Dr. Francis E. Griggs, Jr. P.E. & PLS at the Pedagogium in nearby Erfurt, he was on a feeder canal to the Pennsylvania Canal, enrolled in the prestigious Berlin Bauaka- followed by location surveys for the Allegheny® demi in Berlin where he studied engineering and Portage Canal between Johnston and Hol- under Johann Eytelwein and philosophy un- lidays which was completed in mid 1839. His der Georg Hegel. Then he embarked on the next project was locating a line for the Har- mandatory three-year on-the-job training. Af- risburg and Pittsburgh Railroad across the Al- ter graduating in 1827, he went to work for legheny Mountains, which took him through the government but found it to be extremely late 1841. bureaucratic. He apparently never took the fi- nal exam to become a Baumeister (Building Master). In 1830, after three years of what he calledCopyright “an army of councilors, ministers, and other officials discussing the matter for ten years, making long journeys, and writing long reports, while money spent in all these preliminaries comes to more than the actual accomplishment of the enterprise,” he decided to go to America. He remembered the words of Hegel, who called America “a land of hope John A. Roebling for all who wearied of the historic armory of Roebling is perhaps the most well known Europe.” He and his brother Carl immigrated American civil engineer of the 19th century to America and found an agricultural utopia Brooklyn Bridge (Courtesy of HAER) due to D. B. Steinman’s book The Builders for Germans who sought to escape the repres- of the Bridge and David McCullough’s The sive conditions rampant in most of Europe at While becoming progressively more respon- Great Bridge. In addition, Ken Burns’ series the time. sible for canal and railroad projects, he never on the building of the bridge expanded his He arrived in Philadelphia August 6, 1831 seemed to have forgotten his interest in sus- reputation significantly. This brief biographi- where he would see the bridges over the pension bridges dating from his last year at cal sketch cannot do justice to a remarkable Schuylkill River by Timothy Palmer and Lew- the Berlin Bauakademi, when he visited an career, but it may create an interest in the is Wernwag. Shortly after he and his brother iron chain suspension bridge in Bamberg, Ger- reader to study the existing books on Roemagazine- went to Pittsburgh via the early Pennsylvania many in 1830. In late January 1840, he wrote ® bling. This article of necessity omits the large canals to Huntington. and then over the Al- to Charles Ellet (see STRUCTURE magazine, numberS of patents heT received, his Rvast con- leghenyU Mountains byC wagon trails toT his des- OctoberU 2006) who Rproposed a wire Esuspen- tributions to the journals of his day, his wire tination. After a brief search for land on which sion bridge over the Schuylkill River in 1839 factory accomplishments and the dozens of to start his community, he purchased a parcel and who was seeking the contract to build a unsuccessful proposals he made for bridges 25 miles north of Pittsburgh in Butler County. bridge on the abutments of Wernwag’s Co- around the country. After a brief summary For the next six years he sought to build up this lossus Bridge that burned in 1838. Ellet was of his early life and engineering accomplish- community, called Saxonburg, by encourag- supportive, but he did not have a contract at ments, this article covers his major suspen- ing more emigrants and clearing more land. In the time. Later Roebling was approached by sion bridges built between 1845 and 1869. 1836, he married another German emigrant, another contractor to assist him in building He was born in Mulhausen, Germany on Johanna Herting, and they had eight children the bridge, as he apparently thought he had the June 12, 1806 the youngest of five children. over the next decade. While successful in his contract. Unfortunately for the contractor, His father ran the local tobacco shop, and his effort to build a community, he found that and Roebling, the contract was later awarded mother aspired for great things from her chil- farming was not fulfilling. The next year to Ellet who built the bridge in 1842. To pro- dren, especially John (Johann). After studying was pivotal in his life as his brother died, he became a United Craig E. Barnes, P.E., SECB States citizen, his first Michael S. Teller, A.I.A. ADVERTISEMENT – For Advertiser ADVERTISEMENT Information, son Washington was Wayne R. Lawson, P.E., SECB born on May 26th, and visit www. he left farming and re- 250 Dorchester Ave., Boston, MA 02127-1835 turned to his engineer- STRUCTURE ing career as a surveyor 617 268.8977 • 617 464.2971 fax [email protected] on the Sandy and Bea- mag.org ver Canal. This brief Structural Engineering, Architecture, assignment was inter- Condition Surveys, Roofing, rupted by the financial Moisture Mitigation Design, panic of 1837. He soon Historical Restoration Allegheny Aqueduct 1845 obtained employment STRUCTURE magazine 79 November 2006 them into place, connecting them with pins to pendulums he placed at the top of his towers to ensure equal pull at the top of each tower. This bridge was opened in February 1845, only eight months after the fire. The bridge description was also carried in the American Railroad Journal in April 1846. For the first time he used diagonal® stays of iron bars, which became characteristic of Roebling bridges. With these two bridges, his reputation spread and placed him on a par with Charles Ellet in the minds of many. It was replaced in 1883 with a bridge designed by Gustav Lindenthal. In 1847, he proposed much longer span Niagara Falls Bridge, Currier and Ives bridges at Niagara Falls, St. Louis, Cincinnati, mote his interests he wrote an article on sus- of 16.5 feet at the top, 14 feet at the bottom and Wheeling in competition with Charles pension bridges in April 1841 in the American and a depthCopyright of 8.5 feet. Towpaths on each Ellet and others. However, Ellet received con- Railroad Journal following Ellet’s article in side were built for mules that pulled the canal tracts to build the Niagara Falls and Wheeling the same journal in 1839. While unsuccess- boats. This bridge opened May 22, 1845. He Bridges, with no action being taken for the ful in gaining his first opportunity to assist immediately wrote an article for the American other two. Ellet opened his Wheeling Bridge in the building of a wire Railroad Journal describing with its 1,010-foot span in 1849 and his 800- cable suspension bridge, his bridge. foot Niagara Bridge in 1848. he turned his interest to Just prior to the open- In 1848, Roebling was approached by the D the design and fabrication ing of his aqueduct, a mas- & H Canal to submit a plan for an aqueduct, of twisted wire cables to be sive fire spread over the city similar to his Pittsburgh structure, over the used on the inclined planes and burned the Wernwag Delaware River at Lackawaxen and another of the Portage Canal. Prior bridge on Smithfield Street over the Lackawaxen River just upstream from to his invention, the ca- Smithfield Street Bridge Monongahela over the Monongahela River its intersection with the Delaware. In com- nal boats were hauled up River Pittsburgh 1846 (built in 1818). Roebling petition with a trussed wooden structure, his inclined planes by 7- to was given the contract to plan was selected. The original method used 9-inch circumference hemp ropes, which had rebuild the bridge as a suspension bridge on to cross the Delaware had not worked and the a very short life. He proposed that he build a the same piers. After rebuilding and raising company was looking at rerouting the canal, twisted wire rope for use by the Canal Com- the piers, he built a bridge with 8 main spans resulting in the need for two river crossings. pany. His request was approved, but he wasmagazine to of 188 feet with two anchor spans, for a total The first bridge, completed in late 1848, was supply the wire rope at his own risk. He built length of 1,500 feet. Due to the small size of a four span bridge with three river piers. In his ropeS on his farm Tat Saxonburg R with the his Upiers, he adopted C cast iron columnsT and earlyU 1849, he completedR the secondE bridge assistance of the residents of the community, fabricated the cables on shore. He then lifted and the canal opened in April 1849 with both and used a ropewalk similar to the method used in hemp rope fabrication. He placed the wire rope into position as a trial, but un- fortunately it broke under the load. It was lat- er determined that someone cut the wire at a splice, and the company authorized Roebling to furnish the plane with new rope. After this he received the contract to replace all hemp ropes with his twisted wire cable. This was the beginning of this type of cable that continues to be used in the present day. In mid May of 1844, he received his next opportunity to build a wire cable suspension bridge when the old 1836 wooden aqueduct built over the Allegheny River was determined to be unsafe. He entered a competition, along with 43 other men, to win a $100 premium to replace the bridge. In August, he was noti- fied that his design for a bridge in which the trunk carrying the water was supported by wire cables was awarded the premium.